I don’t profess to be a business guru. I merely pass on my own thoughts gained from years of experience. I have no idea where the government are up to in putting agreements in place, but I would guess that many of the smaller ones have already been sorted and will come into play in 2020. The USA, and Trump in particular, will seek to get something in place as soon as possible in order to help his re-election. The EU will put enough in place by the end of 2020 to extend or allow free trade, with further guarantees of alignment to follow. No one wants to get in the way of trade.
In terms of the NHS, I would guess that Boris will put heavy investment in pretty well immediately....looking forward to the Queens Speech to Parliament....